Coaxial switch



H. R. SMITH COAXIAL SWITCH Aug. 5, 1947.

Filed July 5, 1945 Q r I I.

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3 Sheets-Sheet l INVENTOR HENRY R. SMITH 74 Q/Au,

ATTOR N EY H. R. SMITH COAXIAL SWITCH Aug. 5, 1947.

Filed July 5, 1945 3 Sheets-Sheet 3 TO RECEIVER FIG.6

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INVENTOR HENRY R. SMITH ATTO R N EY Patented Aug. 5, 1947 COAXIAL SWITCH Henry R. Smith, Dayton, Ohio, assignor to the United States of America, as represented by the Secretary of War Application July 5, 1945, Serial No. 603,393

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 3 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to matched-impedance switching devices, and particularly antenna switches.

Switches employed in switched cardioidal pattern antennae, when operated in the higher radio frequency bands, for instance the 120 megacycle band or higher, become critical circuit components, since the physical length of the radio frequency conductors will definitely affect phasing and attenuation of the conducted radio frequency energy. This will readily be comprehended when it is realized that a wavelength at 120 megacycle operation is of the order of only 2.5 meters, and becomes shorter as the operating waveband frequency is increased.

While variou types of switches exist for making or breaking a number of circuits simultaneously such devices are impractical when employed for antennae switching since the resultant directional signals. will be broken by annoying clicks at each switching cycle.

To avoid such clicking, attenuation and phase disturbance, the present invention provides a switch, wherein the conductor elements are constructed to match the lead lines of which the switch conductors and contacts form a part. The switch pole employed is bifurcated over a portion of its length so as to yieldingly form electrical connection with stationary, circuit contacts and thus permit breaking one contact by movement of one leg of the bifurcated pole without disturbing the other leg.

Since the most universal type of high radio frequency conductor in use is of the coaxial type, that is, a conductor within a conductor, with a uniform dielectric in between to provide mechanical concentric spacing of the coaxial conductors as well as dielectric insulating properties, the matching lead line sections of the switch are similarly constructed so as to'provide a virtually uniform line throughout the circuit.

Accordingly, the invention has for an object the provision or a switch adaptable for use in a switched antennae system disclosed in an abandoned application of Robert J. Kemper, Serial No. 601,274, filed June 23, 1945, for Wide band homing system, wherein switching alternately to the circuit of a pair of cardioidal pattern receiving antennae is performed to obtain distinguishable, left-right signals for directing a moving vehicle to the remote beacon transmitting the received radio frequency signals.

A further object is the provision of a single pole double throw switch wherein overlap switching may be performed in such manner that breaking of the circuit at one pole occurs after contact is made at the opposite pole.

A further object is the provision of a switch and its housing adaptable for use in high radio frequency apparatus wherein the switch conductors are so proportioned and arranged that energy loss due to impedance mis-match of the components is reduced to a minimum.

These and other objects will appear throughout the specification and will be particularly pointed out in the claims.

For a better understanding of the invention, reference is had to the following description, taken in connection with the accompanying drawings, wherein:

Fig. 1 is an end elevational view of the coaxial switch;

Fig. 2 is an end view, partly in section, of the switch shown in Fig. 1, the sections being taken along broken line 2--2 of Fig. 4;

Fig. 3 is a bottom interior view of the switch housing;

Fig. 4 is a side elevation partly in section, and partly broken, of the switch housing shown in Fig. 3, the sections being taken along broken line 4-4 of Fig. 3;

Fig. 5 is a partially schematic top plan view of the switch pole actuating cam and lever, the contact arrangement being shown in schematic form for convenience;

Fig. 6 is a side elevation of the cam and lever shown in Fig. 5;

Fig. 7 is a view in perspective, partly broken and in section of the polystyrene contact and pole retainer assembly shown in Figs. 2 and 4;

Fig. 8 is a view in perspective of the bifurcated switch pole assembly.

Referring more particularly to Figs. 1 and 2 the entire switch is housed in a housing I 0 together with the pole actuating mechanism. The housing I0 is illustrated as having a pair of horizontally opposed bored sections 1 l and I2 and an intermediate, vertically disposed, bored section I3. Each of the bored sections is provided with a diametrically uniform tubular dielectric element, also bored, for retention of the switch contact members I1, I 8 and I9, and are made preferably of polystyrene material. For convenience, the dielectric elements H and I5 inserted in the horizontally bored sections II and I2 are combined into a single piece, and an opening extends transversely of its axis to permit the bifurcated legs 20 and 21 of the switch pole [9 of which they form a part, to extend therethrough. It will be understood, therefore, that the horizontal and vertical switch contacts are effectively arranged in T fashion, with the resilient legs 2|] and 2| of the switch pole extending beyond the horizontal dielectric members I4 and I5 and the surface of the housing I through opening 22. The projecting portions of leg 20 and 2| are suitably actuated by a reciprocable lever 23 and thereby perform overlapping switching cycles. Proper adjustment of studs 24 and 25 on lever 23 by increasing or decreasing the gap width between the two legs 20 and 2| will provide the desired amount of switching overlap. That is, one contact may be made to open at the instant the opposite contact is closed, or it may be made to open before or after the other closes.

Referring to Figs. 3 and 4, lever 23 is illustrated as being pivoted on a stud 26 attached to the switch housing l0. While the invention is not limited to any particular lever actuating means, the embodiment herein disclosed employs a double periphery, follower type, motor-driven cam 21, driven by a suitable motor 28 through reduction gearing 30 to 35, inclusive. That is, motor 28 is secured to the switch housing It), with its drive shaft 29 extending through the mounting wall of the housing into a chamber 36 efi'ectively forming a gear housing. A worm 30, mounted on the motor shaft 29, is in driving engagement with worm gear 3| pinned to counter shaft 32, also carrying a worm 33 in driving engagement with a worm gear 34 pinned to cam shaft 35, which shaft has pinned thereon the cam 21 for actuating the switch lever 23.

The cam 21, shown in detail in Figs. and 6, is provided with separate cam peripheries 31 and 38, each provided with lever-actuating cam lobes 4| cooperating with respective pallets or ears 38 and 40 on the lever 21 to sequentially cycle the oscillations of switch lever 23 in predetermined signal cycles, such for instance, as the two short and a long interval of the Morse code letter U on one cam periphery, and the long and two short intervals of the Morse code letter D, these letters preferably being chosen because they form a complementary signal pattern over the two cam surfaces, as is more fully described in said copending application of Kemper Serial No. 601,274.

When cam 21 is rotated through the gearing 30--35 by motor 28, a cam lobe 4| on on cam periphery 31, for instance, actuates the lever 23 in one direction, and the lever 23 is caused to return in the opposite direction by a succeeding lobe 4| on the other cam periphery 38. As will be understood from the above description, the oscillations of lever 23 will alternately break first one circuit between one leg 2| of the switch pole l9 and its switch contact 18, and then the circuit of the other leg 20 with its contact H; the variable amount of lost motion allowed by the spacing beween studs 24 and 25 permittin the desired degree of overlap switching.

For convenience, the switch contacts I1, l8, l9 are provided with female type extensions 42, 43, 44, so that common male type coaxial plug connectors may be removably secured to the switch, the left connector 42 and right connector 43 serving to connect the switch contacts l1 and I8 to a pair of antennae (not shown). After the switch parts are assembled within the bored sections of the housing It) the openings are sealed 4 by plugs 45 and 48 which are threaded to facilitate removal of the contacts for replacement due to wear.

The polystyrene tubular dielectric members l4, l5, and I6 are perforated for insertion therethrough of the threaded shanks of the contact extension members 42, 43, and 44 which are threaded into respective contact members l1, l8, and I9 thereby forming continuous electrical contact and being uniformly and continuously encased within dielectric retainers 41.

The operation of the switch described is as followers: Motor 28, through double reduction worm gearing 30 to 35, rotates cam 21, which oscillates lever 23. Oscillation is accomplished by alternate impingement of the lobes 4| on cam peripheries 31 and 38 against ears or pallets 39 and 40 on lever 23. Oscillation of lever 23, depending on the direction of throw, will separate either of the bifurcated leg extensions 28 or 2| from its respective stationary contact H or I8. Sinc the primary object of the invention is to produce an overlap in this separation, that is, a separation of one pair while the opposite pair is in contact, the studs 24 and 25 on lever 23 will have been adjusted and spaced so that the necssary lost motion will be allowed to produce the desired amount of overlap. Once the studs 24 and 25 are properly adjusted, lock screws 48 may be tightened to prevent displacement of the studs 24 and 25. Thus, a switch is provided which will maintain the impedance characteristic of the line and eliminate clicking of the circuit as well as other objectionable phenomena occurring in conventional type switches due to surge of current when switching circuits, or to any other cause of discontinuity.

While the invention has been illustrated and described in its preferred embodiment it is contemplated that changes in the details thereof may be made without departing from the spirit or scope of the invention as claimed.

Havin thus described the invention, what is claimed is:

1. A high radio frequency switch comprisin a bored and chambered housing, the bored sections extending horizontally and vertically in intersecting T fashion, a pair of tubular dielectric members one of said dielectric members occupying the horizontal bored section, and th other occupying the vertical bored section, a pair of stationary switch contact members oppositely and centrally disposed in spaced relation within said horizontal dielectric member, and a double throw switch pole member centrally disposed within said vertical dielectric member, said switch pole being provided with a pair of spaced resilient extensions forming a bifurcated pole contacting said stationary contacts whereby each le may be alternatel separated from its respective stationary contact to provide overlap switching between said contacts. 2. A high radio frequency switch comprising a vbored housing, the bored sections extending horizontally and vertically in intersecting T fashion, a pair of tubular dielectric members, one of said dielectric members occupying the horizontal bored section of said housing and having a perforation therethrough, and the other dielectric member occupying the vertical bored section, a pair of stationary switch contact members oppositely and centrally disposed in spaced relation within said horizontal dielectric member. a double throw switch pole member centrally disposed within said vertical dielectric member and having spaced, resilient extensions forming bifurcated Dole legs extending through said perforation in said horizontal dielectric member between the adjacent ends of the stationary contact members and normally in contacting circuit-making position therewith, and actuating means operable to alternately actuate said legs for alternately breaking the circuit of each leg with respect to its adjoining stationary contact.

3. A high radio frequency switch comprising a bored housing, the bored sections extending horizontally and vertically in intersecting T fashion, a pair of tubular dielectric members, one of said dielectric members occupying th horizontal bored section of said housing and having a per- Ioration therethrough, and the other dielectric member occupying the vertical bored section, a pair of stationary switch contact members oppositely and centrally disposed in spaced relation within said horizontal dielectric member, a double throw switch pole member centrally disposed within said vertical dielectric member, and having spaced, resilient, extensions forming bifurcated pole legs extending through said perfora- 6 tion in said horizontal dielectric member between the adjacent ends of said stationary contact members, female plug extension members secured to and extending outwardly from said stationary contacts and from said switch pole member and similarly encased in tubular dielectric members retained within outer tubular housing extensions, and switch pole actuating means for actuating said switch pole legs whereby a continuous matched line impedance characteristic is maintained throughout the switch circuit and its associated circuit lines.

' HENRY R. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,323,646 Collins July 6, 1943 2,256,090 Ilberg et a1 Sept. 16, 1941 2,212,230 Goldmann Aug. 20, 1940 

